DE4310053A1 - Hydrogenation catalyst, a method of preparation and use - Google Patents

Description

The present invention relates to a reduced hydrogenation catalyst, which consists of nickel, nickel oxide, magnesium oxide and a water-insoluble carrier material.

Catalysts based on nickel as an active catalyst Part of the gate for the hydrogenation of aldehydes belong to the State of the art.

In EP-A 0 322 049, a hydrogenation catalyst consisting of

• 1) a molar ratio of SiO ₂ / Ni = 0.15-0.35
• 2) a molar ratio of (Mg; Ba) / Ni = 0-0.15

described in which a part of the nickel in metallic Form is present.

The known hydrogenation catalysts based on nickel can in the hydrogenation of aldehydes only at hydrogenation temperature up to about 100 ° C are used as with increasing Hydrogenation formed undesirable by-products which are partly only by an elaborate distillery tion can be separated.

It was therefore the task of a hydrogenation to provide at high throughput speeds temperatures and hydrogenation temperatures above 110 ° C a high selectivity and degrees of conversion of more than 99.5% having.  

Surprisingly, this task could be achieved with a hydrogenation catalyst to be solved

25 to 50% by weight nickel (metallic)
10 to 35% by weight nickel oxide
4 to 12% by weight of magnesium oxide
1 to 5% by weight of sodium oxide
Rest carrier material

and the sum of nickel and nickel oxide is 40 to 70% by weight, the hydrogenation catalyst having a BET surface area of 80 to 200 m ² / g and a total pore volume of 0.35 to 0, determined by Hg porosimetry, 6 ml / g, and the total pore volume is divided into

30 to 60% by volume with a pore radius of 40 Å,
4 to 10% by volume with a pore radius of <40 to 300 Å,
30 to 60% by volume with a pore radius of <300 to 5000 Å.

The hydrogenation catalyst according to the invention may also be chosen wise and preferably be characterized

• a) that 5 to 10 atomic layers on the surface of Hydrierka talysators, determined after the SAM investigation,

18 to 30, preferably 20 to 28 atom% Ni
1.2 to 3.0, preferably 1.5 to 2.5 atom% Na
2.8 to 4.8, preferably 3.2 to 4.5 atom% Mg

contain;

• b) that the metallic nickel surface has a surface area of from 100 to 130 m ² / g of Ni determined by the chemical sorption of hydrogen;
• c) that it as support material alumina or Siliziumdi oxide, in particular as silicic acid, silica gel, kieselguhr or silica.

The invention further relates to a process for the manufacture ment of the hydrogenation catalyst, which characterized is that in a precipitation stage from a green catalyst Nickel salt, magnesium salt and soda, as well as carrier material represents, this green catalyst after separating the mother louse and partial washing in alkali solution aufschlämmt of the liquid phase separates, dries and the dried Green catalyst treated with hydrogen until 42 to 83 % By weight of the total nickel content in metallic form lie.

An optional and preferred method implementation is ge give, if you can

• d) in the precipitation step in a 95 to 100 ° C hot 0.9 to 1.1 molar sodium carbonate solution 95 to 100 ° C hot aqueous solution containing 0.5 to 0.8 mol / l nickel salt and 0.1 to 0.2 mol / l magnesium salt, to a molar ratio of Na ₂ CO ₃ : (Ni + Mg) = 1: 0.60 to 0.6 5 stirred and then immediately added within 0.5 to 5 minutes, the carrier material and the green catalyst formed filtered from the mother liquor, par tially washed with hot water until the effluent washing water has a Leitfä ability of 1500 to 2000 μS; then the Grünkataly capacitor suspended in a 1 to 3 times the amount of water and stirred with 0.06 to 0.08 moles of sodium hydroxide or 0.03 to 0.04 moles of soda per mole of nickel used in the precipitation step amount of nickel and stirred for 1 to 5 hours at a temperature of 40 to 60 ° C the green catalyst from the Sus pension separates;
• e) reduced from the suspension and dried green catalyst at a temperature of 350 to 450 ° C reduced by the dried green catalyst with 0.5 to 5.0 Nm ³ / h reducing gas per kg green catalyst, wherein the reducing gas 80 to 100 vol Contains% hydrogen, treated.
• f) 1 to 3 Nm ³ / h reduction gas per kg of dried Grünkata lysator begins.

For better shaping, the hydrogenation catalyst can be 0.5 add up to 5% by weight of graphite.

The hydrogenation catalyst according to the invention can be used for the hydrogenation propanal and n-butanal and i-butanal, preferably at 110 to 160 ° C are used.

With the hydrogenation catalyst according to the invention is the hydrie tion of propanal and butanal with simultaneous recovery of water vapor with overpressure to improve the host efficiency of hydrogenation feasible. Opposite übli Hydrogenation hydrogenation catalysts at elevated Catalyst load of 0.8 to 1.0 kg / h of aldehyde per kg Catalyst can be performed.

The selectivity is greater than 99.5%, usually greater than 99.9%; About 0.01% of the aldehyde used remain in the Finished product. Less than 0.1% of the aldehyde is in Koh lenmonoxide, ethers, acetals and esters.  

In the hydrogenation of n-butanal, the formation of Dibu tylether below 50 ppm, resulting in a distillation of the finished product can be omitted.

In the hydrogenation of n-propanal, the formation of di propyl ether below 20 ppm.

Applied examination methods 1. BET Surface Determination

The method for the determination of the BET total surface area after Brunauer, Emmett and Teller is in J. Amer. Chem. Soc. 60 (1938), page 309.

2. Pore volume determination by Hg porosimetry (Total pore volume and pore distribution)

The method for pore volume determination by Hg-Poro simetry up to 3900 bar according to H.L. Ritter, L.C. Drake is in Ind. Engng. chem. analyte. Edit, 17 (1945) 782 described ben.

3. Surface removal by chemisorption

The method for determining the nickel surface by Chemisorption of hydrogen taken up at 20 ° C Menge is in J. of Catalysis 81 (1983) 204 and 96 (1985) 517 described.

4. Pore radius determination

The pore radius determination method is described by S.J. Gregg, K.S.W. Sing, Adsorption Surface Area and Porosity, Academic Press New York-London (1967), pages 160-182 described.  

5. Surface investigation with SAM spectroscopy (Scanning Auger Microprobe)

The investigations were carried out with the SAM spectrometer PHI 660 from Perkin-Elmer.

The samples to be examined were evacuated to a vacuum of 1 × 10 ^-8 Torr in a sample chamber by means of a turbomolecular pump.

An electron gun delivered the electron beam, with the sample was shot at. Due to strong Aufla The samples were soge by the electron flow called MULTIPLEX measurements at 5 different locations each performed the sample, with only the energy ranges of expected elements were sampled to a possible As short as possible to reach.

The SAM Exam Method is described in "Practi cal surface analysis by Auger and x-ray photoelectronic spectroscopy "by D. Briggs and M. Seah, John Wiley and Sons, New York, London (19B3), pages 217 ff and 283 ff.  

The measurement and analysis of the emitted from the sample AUGER electrons were made using a cylindrical Mirror analyzer.

In the investigations, the following conditions ge chooses:

Energy resolution (E / E): 0.6%
Excitation energy: 10 kV / 10 mA
Lateral resolution: approx. 220 nm.

The quantitative evaluation was the sensitivity Factors of Pure Elements that are in the "Handbook of Auger Spectroscopy "are published.

The corresponding values were measured and evaluated the elements nickel, sodium and magnesium.

Hydrogenation catalyst properties

The special physical and chemical properties of the hydrogenation catalyst, which is ultimately the prerequisite for its advantageous hydrogenation behavior are in the we sentlichen by the following features and measures in the Production achieved.

In the precipitation step, the common precipitation of basi occurs Scheme nickel-magnesium mixed carbonate and its addition to the carrier material. The precipitation conditions are so ge chooses the proportion of basic Mg carbonate of precipitation in as sparingly soluble form as possible lies.  

The green catalyst obtained in the precipitation step is invented According to only partially washed so far that little out precipitated basic magnesium carbonate from the green catalyst is washed out.

The invention includes the targeted Nachalkalisierung the par tially washed green catalyst, whereby the erforderli enrichment of alkali on the catalyst surface is reached.

The drying of the green catalyst is not critical. you can be used in a relatively wide range of drying conditions For example, in the air flow at 50 to 100 ° C Runaway be led.

Critical and inventive is the reduction of Grünkataly sators to the hydrogenation catalyst. The reduction is so durchzu perform that while maintaining the temperature of 350 to 450 ° C and a hydrogen flow rate of 0.25 to 0.75 m / s only a partial reduction of the nickel-containing Kom component takes place. A degree of reduction of 42 to 83% has proved to be advantageous.

When used in Festbetthydrierungen the Grünkata lysator before drying z. B. to form extrudate, ge dried, reduced and used in this form or stabilized after reduction by treatment with small amounts of O ₂ in N ₂ in a known manner, (H. Blume, W. Naundorf and A. Wrubel, Chem. Techn ., Vol. 15 (1963), page 583).

It has been found that depletion of the surface of the Hydrogenation catalyst to Na an increase of cleavage and side by side caused reactions leading to the loss of value products to lead.

At excessive Na concentrations on the surface of the Hydrogenation catalyst increases the hydrogenation in increase the dimensions. In addition, there is a tendency for education of aldolization products.

The depletion of the surface of the hydrogenation catalyst over Mg leads to an altered, compared to the invention Catalyst unfavorable pore structure and increase the catalyst activity, especially in the hydrogenated pulp temperature range above 100 ° C to form unwanted side products, in particular fission products leads; a high Mg Excess causes an inactivation and thus a low re performance of the hydrogenation catalyst.

The Na content in the surface layer is for the hydrogenation Catalyst for controlling the selectivity and thus the Un Suppression of cleavage and side reactions required. he ranges are the increased Na concentration in the surfaces layer through the slurry of green catalyst in Al potash.

The following examples serve to clarify the present invention without limiting.

example Preparation of the hydrogenation catalyst

1906 g of Ni (NO ₃ ) ₂ · 6 H ₂ O and 355.6 g of Mg (NO ₃ ) ₂ · 6 H ₂ O who dissolved in 10.4 l of water at 99 ° C.

In a stirred tank, 1500 g of anhydrous Na ₂ CO _{3 are dissolved} in 14 l of water at 99 ° C.

With vigorous stirring, then the Ni-Mg solution in 3 run evenly into the soda solution. 230 g of pebbles gur are added in powder form and the formed suspensions Initially stirred for 3 min and then filtered. The filter cake is gewa with 27 l of 70 ° C warm water rule. The last effluent wash had a Leitfä ability of 1800 μS.

The filter cake was in 6000 g of 0.25% strength by weight sodium hydroxide solution and stirred for 2 hours at 50 ° C and egg filtered filter press. The filter cake is pressed treated for 1 minute. The moisture of the filter cake was 82% water. In this form the filter cake became too Thread grain (6 mm ⌀) deformed. The deformed filter cake wur de dried in a drying oven, for 5 hours at 50 ° C, for 3 hours at 60 ° C and for 8 hours at 75 ° C to constant weight.

The green catalyst had the following analysis:

Ni 37.8% by weight MgO 5.2% by weight Na ₂ O 1.1% by weight CO ₂ 6.0% by weight support material 22.7% by weight humidity 6.5% by weight bulk weight 530 g / l

The green catalyst was reduced at 425 ° C within 4 hours. For this purpose, 6 Nm ³ / h of reducing gas were passed over 2 kg of green-grain catalyst. The reducing gas consisted of 99.5% by volume of hydrogen and 0.5% by volume of nitrogen.

In the reduction, a weight loss of 0.76 kg observed.

At a total nickel content of 53% by weight was reduced in the Catalyst a reduction of 72% determined.

Application example 1 Hydrogenation of n-butanal

The catalyst prepared according to Example 1 is in the form of 6 mm tablets (250 ml) in a tubular reactor with heating cooling jacket (inner diameter: 32 mm) initially in hydrogen flow of 730 Nl / h at 4 bar with a Aufheizge speed of 20 ° C / h brought to 120 ° C. Mach Errei chen of 120 ° C, 50 ml / h of n-butanal (liquid) in the upstream of the reactor, 730 Nl / h H ₂ flowed through evaporator fed at 100 ° C evaporator temperature. The H ₂ / butanal vapor mixture is heated in front of the reactor in a Vorer heater to reactor temperature. After 12 h, the task amount of n-butanal is increased to 75 ml / h and after a further 12 h to 100 ml / h. Thereafter, the increase in Buta-nal task takes place in each case in rates of 25 ml of n-butanal in the 24 Stun the interval. At the same time, in the course of butanol addition, the preheater and reactor temperatures are increased as follows:

The amount of H ₂ is kept constant during the start-up period and during continuous operation.

The resulting vaporous hydrogenation product is cooled and analyzed.

The hydrogenation product consists of 99.9% by weight of n-butanol and contains less than 0.1% by weight unreacted n-butanal and <20 ppm of di-n-butyl ether as a by-product.

In addition to the hydrogenation product about 0.4 kg of H ₂ O vapor in continuous operation of <1.8 bar (vapor pressure according to the Re actuator temperature) per kg of n-butanal used recovered.

Application Example 2 Hydrogenation of propanal

The catalyst prepared according to Example 1 is in the form of 6 mm tablets (250 ml) in the same reactor system as in Application Example 1, first in H ₂ stream (730 Nl / h) at 3.5 bar at a heating rate of 20 ° C. / h heated to 125 ° C. Thereafter, over a period of 12 h initially 50 ml Propanal (liquid) fed into the evaporator. The injected amount of propanal is increased at intervals of 12 hours by 25 ml to 150 ml / h. Upon reaching the feed rate of 150 ml / h, the Vorerhit zer and reactor temperature is increased to 128 to 130 ° C. The resulting hydrogenation product is condensed by cooling and analyzed. It consists of about 99.9% by weight of n-propanol and <0.1% by weight unreacted propanal. As by-products, <100 ppm 2-methylpentanone-3 and <20 ppm di-n-propyl ether are analyzed.

As in Application Example 1 is also in the hydrogenation of Propanal with the catalyst according to the invention the extraction of water vapor (1.3 bar) possible.

Application Example 3 Hydrogenation of i-butanal

For the hydrogenation of i-butanal, the catalyst (250 ml) from Example 1 was heated under the same conditions as in application example 1 under H ₂ to 120 ° C. Subsequently ßend initially 50 ml / l of i-butanal were fed. Hydrogenation pressure (3.5 bar), reactor temperature (120 ° C) and H ₂ -speed speed (730 Nl / h) were kept constant. The resulting hydrogenation product consisted of 99.95% by weight of i-butanol and contained 0.03% by weight of unreacted i-butanal and <20 ppm of di-i-butyl ether. The hydrogenation of i-butanal on the catalyst according to the invention gives H ₂ O vapor of 1.8 bar.

Comparative example Hydrogenation of n-butanal

In the same tube reactor as in Application Example 1 who the 250 ml of commercial 55/5 TST nickel catalyst (HOECHST AG) in the form of 6 mm tablets in a stream of hydrogen of 730 Nl / h at 3.5 bar with a heating rate from 20 ° C / h to 100 ° C heated.

Thereafter, 50 ml / h of n-butanal (liquid) in the, upstream of the reac tor, of 730 Nl / h H ₂ flowed through evaporator fer fed at 100 ° C. Before entering the reactor, the H ₂ -Butanal vapor mixture is heated in a preheater on reac tortemperatur.

After 12 hours, the charged amount of n-butanal is increased to 75 ml / h and up to 150 ml / h at intervals of 12 hours. Under these reaction conditions, a hydrogenation product was obtained, which from 98.9 wt% n-butanol, 0.3 wt% acetals, 0.3 wt% trimeric aldolization of Bu tanals, 0.1 wt% hydrocarbons, 0.1 wt% 2-ethylhexanol, 0.1% by weight of di-n-butyl ether and 200 to 300 ppm of C ₄ / C ₄ ester.

From the n-butanal used were 1.0 to 1.2% by weight Hydrogenolysis converted to propane and methane, which in the ab flowing hydrogenating hydrogen are contained.

Compared to the catalyst of the invention occur in Ver Use of the commercial catalyst already at 100 ° C. considerable proportions of by-products. Especially tough rig is for the production of pure n-butanol the destilla tive separation of the di-n-butyl ether, which with increasing Ester contents lead to disproportionate losses of n-butanol leads.

A further disadvantage over the catalyst according to the invention is the relatively high loss of product of value (<1% by weight) caused by hydrogenolysis.
If the task of n-butanal is increased above 150 ml / h, in particular the formation of di-n-butyl ether and cleavage products by hydrogenolysis increases.

Same effects arise with increasing the hydrogenation temperature.

Compared to the catalyst according to the invention can with the catalyst of the prior art only a maximum of 60% of Aldehydmenge be implemented, which also verun more purified hydrogenation products are obtained.  

Another disadvantage is the limitation of Hydiertempera ture to a maximum of 100 ° C, in which no use of H ₂ O vapor is possible.

Claims (10)

1. hydrogenation catalyst containing nickel, nickel oxide, Magne siumoxid, sodium oxide and a water-insoluble carrier material, characterized in that the Hydrierkataly capacitor from
25 to 50% by weight nickel (metallic)
10 to 35% by weight nickel oxide
4 to 12% by weight of magnesium oxide
1 to 5% by weight of sodium oxide
Rest carrier material
and the sum of nickel and nickel oxide is 40 to 70% by weight, the hydrogenation catalyst having a BET surface area of 80 to 200 m ² / g and a total pore volume of 0.35 to 0, determined by Hg porosimetry, 6 ml / g, and the total pore volume is divided into
30 to 60% by volume with a pore radius of 40 Å, 4 to 10% by volume with a pore radius of <40 to 300 Å,
30 to 60% by volume with a pore radius of <300 to 5000 Å. 2. hydrogenation catalyst according to claim 1, characterized in that 5-10 atomic layers on the surface of the hydrogenation catalyst, determined by the SAM investigation,
18 to 30, preferably 20 to 28 atom% Ni
1.2 to 3.0, preferably 1.5 to 2.5 atom% Na
2.8 to 4.8, preferably 3.2 to 4.5 atom% Mg
contain. 3. hydrogenation catalyst according to any one of claims 1 and 2, characterized in that the metallic nickel upper surface a, by chemisorption of hydrogen be true surface of 100 to 130 m ² / g Ni. 4. hydrogenation catalyst according to claims 1 to 3, characterized characterized in that it comprises alumina as support material or silica, especially as silica, pebbles gel, diatomaceous earth or silica. 5. Process for the preparation of the hydrogenation catalyst according to at least one of claims 1 to 4, characterized gekenn draws that one in a precipitation a Grünkataly nickel salt, magnesium salt and soda and trä germaterial produces, this green catalyst after Ab Separate the mother liquor and partial washing in Alka Slurry dissolves, separates from the liquid phase, Dries and the dried green catalyst with water treated up to 42 to B3 wt% of the total nickel share in metallic form.   6. The method according to claim 5, characterized in that in the precipitation step in a 95 to 100 ° C hot 0.9 to 1.1 molar sodium carbonate solution 95 to 100 ° C hot aqueous solution containing 0.5 to 0.8 mol / l nickel salt and 0.1 to 0.2 mol / l magnesium salt, up to a molar ratio of Na ₂ CO ₃ : (Ni + Mg) = 1: 0.60 to 0.65 and then immediately within from 0.5 to 5 minutes, the carrier material is added and the green catalyst formed filtered from the mother liquor, washed with hot ßem water partially until the effluent Waschwas has a conductivity of 1500 to 2000 μS; then the green catalyst suspended in a 1 to 3 times the amount of water and stirred with 0.06 to 0.08 moles of sodium hydroxide or 0.03 to 0.04 moles of soda per mole in the precipitation te te amount of nickel and stirred for 1 to 5 hours at a Temperature of 40 to 60 ° C separates the green catalyst from the suspension. 7. The method according to any one of claims 5 and 6, characterized in that one reduces the separated from the suspension and dried green catalyst at a temperature of 350 to 450 ° C by adding the dried green catalyst with 0.5 to 5.0 Nm ³ / h reducing gas per kg of green catalyst, wherein the reducing gas contains 80 to 100% by volume of hydrogen treated. 8. The method according to claim 7, characterized in that one uses 1 to 3 Nm ³ / h of reducing gas per kg of dried green catalyst. 9. Use of the hydrogenation catalyst for the hydrogenation of Propanal, n-butanal and i-butanal.   10. Use of the hydrogenation catalyst according to claim 9, characterized in that the hydrogenation catalyst used at 100 to 160 ° C.